Axa will retain the Bluefin trading name. Its other operations, including Bluefin Insurance Group and Bluefin Personal Consulting, do not form part of the transaction.

Mike Addenbrooke, current managing director of Capita Hartshead, will become non-executive chairman of Capita Hartshead when the deal is completed. He said: “Employers face major challenges over the coming months and years.

“These include both the evolving legislative and regulatory landscape, such as auto-enrolment, and continuing social and behavioural change.

“This merger will add considerable new market reach and broader expertise to our range of services. The deal will mean Capita has a stronger presence in investment consultancy, the insured pensions sector, flexible benefits, and health and risk benefits, allowing us to better help employers meet the challenges ahead.”

Nick Burns, chief executive of Bluefin Corporate Consulting, will become chief executive of the combined business. He added: “I believe that Capita Hartshead’s strength in pensions administration, actuarial and consulting, together with Bluefin’s employee benefits expertise and market-leading online technology, will combine to deliver a wide range of services.

“With the full backing of a FTSE 100 company, this new business will be able to provide genuinely innovative solutions to the rapidly evolving and increasingly dynamic employee benefits market.”

Paul Evans, group chief executive of Axa UK and Ireland, added: “Following the sale of the Axa life business in 2010, and in particular the corporate pensions business, the consulting services offered by Bluefin Corporate Consulting are no longer aligned to our long-term strategy and core lines of business.

“We are pleased to have entered into an agreement with Capita which will ensure that Bluefin Corporate Consulting and its customers benefit from the scale and market presence offered by becoming part of Capita’s enlarged employee benefits operation.”